​​How does Automatic Display Brightness control work in devices like smartphones?

The device may automatically control the display brightness using different methods. In one embodiment, the device may measure the ambient light (lux) using a front-facing ambient-light sensor (ALS) and a rear-facing ALS. In one embodiment, in addition to the front-facing and rear-facing ALSs and/or front and rear cameras, the device may utilize edge ALSs. In one embodiment, in addition to the front-facing and the rear-facing ALSs, the device may use a combination of other sensors, such as proximity sensors, a radar-based sensor, or accelerometers to determine the orientation of the device (e.g., laying on a flat surface) and ignore measurements from one of the ALSs. In one embodiment, in addition to ALSs and/or other sensors, the device may also use the context in which the user is using the device, such as what application software the user is currently using. In one embodiment, the device may use an advanced sensor-fusion algorithm that takes raw red, green, and blue (RGB) data from the front and rear cameras, combines them with the device’s orientation, estimates the level of ambient lux, and automatically controls the display brightness without using ALSs.